| 본문 : Ocular myasthenia gravis (MG) is an autoimmune disease that affects extraocular muscles, levator palpebrae superioris, orbicularis oculi, or a combination of these and has clinical manifestations including ptosis and diplopia. Any of extraocular muscles may be involved, and any type of strabismus is possible in patient with ocular MG. We report a case of ocular MG presenting with bilateral pseudo-internuclear ophthalmoplegia (INO).
A 66-year-old male was consulted our clinic for insidious onset of horizontal diplopia for 1 week. The symptom had diurnal variation and was aggravated with fatigue. Past medical history was notable for diabetic mellitus. There was no ocular pain. There was intermittent upper eyelid dropping of right eye. The best corrected visual acuity was 20/25 in right eye and 20/20 in left eye. The pupils showed normal response to light and near stimulation in both eyes. The extraocular examination showed 20 prism diopters (PD) of exotropia and 4 PD hypertropia of right eye at primary gaze with adduction limitation of the both eyes. Magnetic resonance imaging of brain showed no abnormal findings of brain stem. The serologic work-ups was conducted and anti-acetylcholine receptor antibody test was 0.64 nmol/L (0-0.5). The ocular myathenia gravis was diagnosed and a pyridostigmine and steroid were prescribed. The symptom of patient showed improvement with medications.
The ocular MG can be mimicked by many other ocular motility disorders involving the extraocular muscles, and bilateral pseudo INO is one of these disorders. |